A disposable diaper is produced in, for example, a way described below.
First, constituents composed of a main body portion that extends from a front belly part to a back part via a crotch part and four side pieces that extend from both ends in the longitudinal direction of the main body portion in their width direction are produced.
Next, in a state in which the main body portion is folded in two so as to make the respective side pieces overlap each other, the respective side pieces are joined to each other to form a pair of portions (hereinafter referred to as side portions) that covers the side surfaces of the lumbar part of a wearer.
Then, the ends of the respective side pieces are cut off uniformly for the respective side portions. This operation is performed using a slitter device described in, for example, Japanese Patent No. 4799949.
The slitter device described in Japanese Patent No. 4799949 has a lower blade (hereinafter referred to as a driving blade) that rotates with the operation of a driving motor, an upper blade (hereinafter referred to as an facing blade) that is provided so as to face the driving blade and compresses webs (respective side pieces) between the facing blade and the driving blade to be cut off, and a guide plate that guides the webs between the driving blade and the facing blade while supporting the lower surfaces of the webs.
In the slitter device described in Japanese Patent No. 4799949, however, the webs guided between the driving blade and the opposing blade are only placed on the guide plate. Therefore, the cutting positions of the respective side pieces cannot be accurately managed.
That is, in the slitter device described in Japanese Patent No. 4799949, the respective side pieces are freely movable with respect to the respective blades in a direction orthogonal to their movement direction until they are cut off between the driving blade and the opposing blade. Therefore, the cutting positions fluctuate with respect to the positions of the respective side pieces.